Area Forecast Discussion
Issued by NWS Sacramento, CA

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FXUS66 KSTO 302150
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
250 PM PDT SAT APR 30 2016

.Synopsis...
Breezy north winds continue into Sunday, though not as strong as
today. Milder temperatures. Mountain shower chances return Sunday
afternoon. Better chance of more widespread showers and
thunderstorms by the middle of next week.

&&

.Discussion...
Breezy day across the region as last night`s weather system moves
into Arizona and high pressure builds along the West Coast. Skies
are clear across most of interior NorCal this afternoon except for
cloudiness packed up along the northern Sierra crest from easterly
flow. Temperatures are a mixed bag today with mountain areas
generally cooler than 24 hours ago with readings in the 40s and
50s (continuing cold advection in the mid-levels) while the
Central Valley is running about 4-8 degrees warmer with temps in
the upper 70s and lower 80s under sunshine and some compressional
warming.

Northerly surface pressure gradients have begun to relax a bit,
and will decrease further tonight as the gradient shifts and
becomes more northeasterly by 12Z Sunday. While breezes will
continue overnight, most areas will see gusts drop below advisory
levels by late this afternoon. Breezy northerly winds will
continue into Sunday.

Eastern Pacific ridge develops into blocking high over the
northern Rockies on Sunday allowing some portion of the SW low to
retrograde back into NorCal from the east. This will bring a
return of mainly diurnal showers and thunderstorms to the
mountains Sunday and Monday. Valley high temperatures will be
mainly in the low to mid 80s.

Next upstream trough forecast to approach Tuesday marking the
beginning of the trend back toward cooler temps along with more
unsettled weather for NorCal heading into mid-week.

&&

.Extended Discussion (Wednesday thru Saturday)...
A high amplitude trough of low pressure is forecast to be
positioned in the eastern Pacific and move into NorCal Wednesday.
The incoming storm system will bring the needed lift behind enough
moisture to bring showers and thunderstorm chances for the entire
forecast area. A cool down of temperatures is expected with a
return to near normal high temperatures in the low to mid 70s in
the valley, 50s to 60s in the foothills, and the low to mid 40s in
the higher elevations.

Models are in fairly good agreement as to the timing and spatial
extend of the upper level low pressure, and the system should stall
out over the west coast for a few days.  As a result of the
lingering system, cooler temperatures and chances for showers and
thunderstorms will continue through the end of the week.

&&

.Aviation...
VFR conditions are expected at the terminals for the next 24
hours. The transition between low and high pressure over NorCal
will bring gusty conditions in the valley through late evening for
the Sacramento area and southward, while gusty conditions will
continue in the north valley overnight through Sunday.

&&

.STO Watches/Warnings/Advisories...
Wind Advisory until 5 PM PDT this afternoon for Carquinez Strait
and Delta-Central Sacramento Valley-Clear Lake/Southern Lake
County-Mountains Southwestern Shasta County to Northern Lake
County-Northern Sacramento Valley-Northern San Joaquin Valley-
Southern Sacramento Valley.

&&

$$



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